<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<input type="button" value="点击按钮" onclick=alert("按钮被点击") />
		<select onchange=alert(this.value)>
			<option value="1">1</option>
			<option value="2">2</option>
			<option value="3">3</option>
			<option value="4">4</option>
		</select>
	</body>
</html>
